40 . HOUSEHOLD INSECTS 



covers, behind pictures, in wardrobes, nestled in bonnets 

 and hats, under the edges of carpets, etc." They were 

 also said to be found in incredible numbers under buildings 

 between the earth and the floor. 



Lintner gives several instances of the occurrence of 

 these cluster-flies in buildings in different localities in 

 New York State. 



The cluster-flies enter a building in the fall one by one 

 through cracks and crevices and afterwards gather in 

 clusters. In the spring they swarm on windows on warm 

 sunny days. When crushed some say they emit an odor 

 like honey, others say the odor is disagreeable. 



Its life history. — Almost nothing is known of the life 

 history of this fly, as common as it is. Riley states that 

 he found the puparia of the cluster-fly in the roots of grass 

 about three inches below the surface of the ground. 

 Howard says that a single specimen of this fly was reared 

 from cow-manure in the Insectary of the Bureau of Ento- 

 mology at Washington. J. S. Hine of Columbus, Ohio, 

 writes Howard that he reared a number of specimens of 

 cluster-flies from cow droppings in the pasture. 



Robineau Desvoidy remarks that the eggs of the mem- 

 bers of the genus Pollenia are laid in manure and in de- 

 composing animal and vegetable matter. 



Methods of control. — W T e are probably partly safe, 

 at least, in assuming that the cluster-flies lay their eggs 

 on decaying vegetable matter and that the larvae live in 

 these substances. If correct, then the same methods 

 used in the control of the house-fly will also be of benefit 

 in controlling the cluster-fly. However, it is probable 

 that the cluster-fly breeds over much wider areas, — away 

 from buildings, out in the fields and possibly in the woods. 



